VARIABLE INTEREST ENTITIES - Schedule of Variable Interest Entities (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	$ 233,488	$ 223,720
Liabilities for commitments to fund tax credit investments	211,502	201,492
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	2,831	2,516
Variable Interest Entity, Not Primary Beneficiary | Total tax credit equity investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	2,672	2,359
Variable Interest Entity, Not Primary Beneficiary | Affordable housing tax credit investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	2,631	2,357
Variable Interest Entity, Not Primary Beneficiary | Other tax credit equity investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	41	2
Variable Interest Entity, Not Primary Beneficiary | Other unconsolidated investments
Variable Interest Entity [Line Items]
Total affordable housing tax credit and other unconsolidated investments (maximum loss exposure)	159	157
Variable Interest Entity, Not Primary Beneficiary | Commitments to tax credit investments
Variable Interest Entity [Line Items]
Liabilities for commitments to fund tax credit investments	$ 1,295	$ 1,214